The picture shows a phase in a motor drive. Are C4B and R5B absorbing spike voltages? The voltage is 60V. How is this type selected?
Hamilton ポストする October 29, 2020
Filtered, filter high frequency interference;
In addition, inside the MOS tube: there is a capacitor between GS;
The capacitance value is calculated according to the signal frequency.
Auston ポストする October 29, 2020
The capacitor is an absorbing capacitor, which needs to be selected according to the voltage spike generated by the parasitic inductance on the bus. The high-frequency non-inductive capacitor should be placed as close as possible to the MOSFET on the PCB.
That resistor seems to be the discharge resistor of the bus capacitor, the circuit is missing part.
Marcia ポストする October 29, 2020
The resistor is to provide a virtual ground for the upper bridge drive, allowing the upper bridge to open normally when no load is connected.
